(1) Field of the Invention
The invention relates to a novel protein having a cell growth stimulating activity, a composition containing said protein, and a method for producing said protein. The novel protein of this invention is useful as a wound treatment agent and a promoting agent in the synthesis of DNA.
(2) Description of the Prior Art
It has been known that a nucleoside phosphotransferase-containing fraction of broth and cells which cultured Clostridium perfringens thereon is effective as a wound treatment agent (Japanese Patent unexamined Publication No. 147908/1979). It has also been disclosed that a polypeptide, of a molecular weight of about 5,300 having 52 amino acids, isolated from mammalian body fluid (Japanese Patent unexamined Publication No. 38716/1982) and a composition containing each of the essential and semi-essential amino acids and malic acid (Japanese Patent unexamined Publication No. 80316/1982) are effective for treating wounds.
An oligosaccharide (composed of galactose and glucose) obtained by culturing certain species of organisms of the genus Bifidobacterium is also known as a cell growth factor substance (Japanese Patent unexamined Publication No. 104885/1980).
Other wound treatment agents heretofore known involve Zinc Oxide Ointment, Solcoseryl Ointment.RTM. (a deproteinized extract from young bovine whole blood), ZILDASAC.RTM. (Bendasac), Elase Ointment.RTM. (containing fibrinolysin, deoxyribonuclease, and chloramphenicol), Cartabes.RTM. (containing carbazochrom, and alkyldiaminoethylglycine hydrochloride), AD Ointment.RTM. (fortified cod-liver oil), Alkixa Ointment.RTM. (aluminum chlorohydroxyallantoinate) and Oronine Ointment.RTM. (chlorohexidine analogs).
Although effectiveness of the above ointments varies, any wound treatment agent desirably exhibits reliable and efficient granulation tissue-growing activity and epidermis-forming activity on the wounded portion. From this viewpoint, the development of improved wound treatment agents is in great demand.
The healing process of wound healing is very complicated physiologically. The process may be generally regarded as the successive development of various cells, followed by absorption of foreign matter, and the resultant destruction of bacteria and repair of the tissue.
When an incision is deep, blood from the ends of the incised blood vessels flows into the gap formed between the severed tissue to fill it up, after which a thrombus is formed to cover the fringes of the wound. The thrombus loses its liquid content within several hours and the surface dries to form a crust, which protects the wounded surface. The wound area is accompanied by inflammation, which starts with the inflow of body fluid into the wound surrounded by the thrombus. Inflammation thus initiated will cause the patient to feel a swelling pain. After a lapse of about 6 hours, various types of white blood cells will begin to move into the wounded portion to remove and break down the damaged cells, bacteria and other foreign matter. Fibroblasts in the dermis will then enter the wound to synthesize collagen fibers and other proteins to form scar tissue inside the corium. On the other hand, the epidermis (or the surface layer) will form a surface similar to the original skin before the patient was wounded. When formation of this layer is completed, the crust will peel off and the wound will be completely healed.
Although the process of the treatment of wounds has been thus clarified, drugs for wounds have not previously been sufficiently effective.